import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
import { formatSkillsForPrompt, loadSkills } from "@mariozechner/pi-coding-agent";
import { registerPromptSegment } from "../../../vera-prompt-inspector/src/registry";

// Vera's prompt-rules extension replaces Pi's default base prompt
// entirely, which incidentally throws away the skills section Pi would
// normally inject via `formatSkillsForPrompt`. This extension re-adds
// it as a dedicated, inspector-visible segment, using the same Pi APIs
// so the format stays in sync with Pi's own behaviour.

export default function skillCatalog(pi: ExtensionAPI) {
  pi.on("before_agent_start", async (_event, ctx) => {
    // skillPaths is required to be iterable by Pi (skills.js:352);
    // pass an empty array even when we only want default discovery.
    const result = loadSkills({
      cwd: ctx.cwd,
      skillPaths: [],
      includeDefaults: true,
    });
    const block = formatSkillsForPrompt(result.skills);
    // `formatSkillsForPrompt` returns text with a leading "\n\n"; strip
    // it so the finalizer in vera-prompt-inspector can add its own
    // separator consistently.
    const text = block.replace(/^\n+/, "");
    const visibleCount = result.skills.filter((s) => !s.disableModelInvocation).length;
    registerPromptSegment({
      id: "skills",
      label: "skill catalog",
      category: "catalog",
      kind: "cached-per-session",
      text,
      details: [
        { label: "skills", value: String(visibleCount) },
        { label: "diagnostics", value: String(result.diagnostics?.length ?? 0) },
      ],
    });
    return undefined;
  });
}